Editing Interactome (section)

===Network structure and topology===
Interaction networks can be analyzed using the tools of [[graph theory]]. Network properties include the [[Degree (graph theory)|degree]] distribution, [[clustering coefficient]]s, [[betweenness centrality]], and many others. The distribution of properties among the proteins of an interactome has revealed that the interactome networks often have [[Scale-free network|scale-free topology]]<ref>{{Cite journal | author = [[Albert-László Barabási]] & [[Zoltan N. Oltvai]] | title = Network biology: understanding the cell's functional organization | journal = [[Nature Reviews. Genetics]] | volume = 5 | issue = 2 | pages = 101–113 | date = February 2004 | doi = 10.1038/nrg1272 | pmid = 14735121 | s2cid = 10950726 }}</ref> where '''functional modules''' within a network indicate specialized subnetworks.<ref name="modules">{{Cite journal | doi = 10.1142/S0219720009004023 | last1 = Gao | first1 = L. | last2 = Sun | first2 = P. G. | last3 = Song | first3 = J. | title = Clustering algorithms for detecting functional modules in protein interaction networks | journal = Journal of Bioinformatics and Computational Biology | volume = 7 | issue = 1 | pages = 217–242 | year = 2009 | pmid = 19226668
}}</ref> Such modules can be functional, as in a [[signaling pathway]], or structural, as in a protein complex. In fact, it is a formidable task to identify protein complexes in an interactome, given that a network on its own does not directly reveal the presence of a stable complex.